Superconducting bearings devices already known include those disclosed, for example, in the specifications of U.S. Pat. Nos. 4,886,778 and 4,892,863.
These superconducting bearing devices have incorporated therein a Type II superconductor, i.e., a superconductor which permits penetration of the magnetic flux of a permanent magnet in a temperature environment which realizes a Type II superconducting state. The superconducting bearing device comprises a permanent magnet mounted on a rotary body, and a Type II superconductor provided on a fixed portion and opposed to the magnet.
However, the superconducting bearing device has the problem of being low in operation efficiency since the device has no mechanism for determining the position of the superconductor and the permanent magnet relative to each other when the device is to be initiated into operation. Further the device has the problem that the rotary body and parts therearound become damaged or broken should the superconductor be made normally conductive (quenched).
An object of the present invention is to provide a superconducting bearing device which is free of these problems.